#include<bits/stdc++.h> #define debug(x) cerr << #x << " " << x << "\n" #define debugs(x) cerr << #x << " " << x << " " #pragma GCC optimize("Ofast") #define int long long using namespace std; mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); int range_rng(int l, int r) { return uniform_int_distribution<int>(l,r)(rng); } vector<int> nodes[200005]; map<int,int> cnt; int h[200005]; int u[200005]; int p[200005]; bool is_leaf[200005]; int leaves[200005]; int sz[200005]; int heavychild[200005]; int pathend[200005]; int stamp[200005]; int revstamp[200005]; int timer,root,ans,n; bool ok; struct Node { int sumodd; int sumeven; int lazy; }; class AINT { public: Node aint[800005]; Node combine(Node a, Node b) { Node c; c.sumeven=0; c.sumodd=0; c.sumeven+=a.sumeven; c.sumodd+=a.sumodd; c.sumeven+=b.sumeven; c.sumodd+=b.sumodd; c.lazy=0; ///lazy e mereu 0 return c; } void prop(int val, int l, int r) { if (aint[val].lazy==0) return; swap(aint[val].sumeven,aint[val].sumodd); if (l!=r) { int mid; mid=(l+r)/2; prop(val*2,l,mid); prop(val*2+1,mid+1,r); aint[val*2].lazy=1; aint[val*2+1].lazy=1; } aint[val].lazy=0; } void build(int l, int r, int val) { if (l==r) { aint[val].lazy=0; aint[val].sumeven=0; aint[val].sumodd=0; if (leaves[revstamp[l]]%2==1) aint[val].sumodd=1; else aint[val].sumeven=1; return; } int mid; mid=(l+r)/2; build(l,mid,val*2); build(mid+1,r,val*2+1); aint[val]=combine(aint[val*2],aint[val*2+1]); } void flip(int l, int r, int val, int qa, int qb) { prop(val,l,r); if (qa<=l && r<=qb) { aint[val].lazy=1; return; } int mid; mid=(l+r)/2; if (qa<=mid) flip(l,mid,val*2,qa,qb); if (qb>mid) flip(mid+1,r,val*2+1,qa,qb); prop(val*2,l,mid); prop(val*2+1,mid+1,r); aint[val]=combine(aint[val*2],aint[val*2+1]); } void add_leaf(int parent) { if (is_leaf[parent]) parent=p[parent]; while (pathend[parent]!=root) { flip(1,n,1,stamp[pathend[parent]],stamp[parent]); parent=p[pathend[parent]]; } flip(1,n,1,stamp[pathend[parent]],stamp[parent]); } void remove_leaf(int parent) { if (is_leaf[parent]) parent=p[parent]; while (pathend[parent]!=root) { flip(1,n,1,stamp[pathend[parent]],stamp[parent]); parent=p[pathend[parent]]; } flip(1,n,1,stamp[pathend[parent]],stamp[parent]); } int query(int l, int r, int val, int qa, int qb) { prop(val,l,r); if (qa<=l && r<=qb) { return aint[val].sumeven; } int mid,ans; ans=0; mid=(l+r)/2; if (qa<=mid) ans+=query(l,mid,val*2,qa,qb); if (qb>mid) ans+=query(mid+1,r,val*2+1,qa,qb); return ans; } } hevi; void dfs(int node, int parent) { leaves[node]=0; sz[node]=1; if (nodes[node].size()==1) { is_leaf[node]=1; leaves[node]=1; return; } int mx; mx=0; for (auto x : nodes[node]) { if (x!=parent) { p[x]=node; h[x]=h[node]+1; dfs(x,node); leaves[node]+=leaves[x]; sz[node]+=sz[x]; if (sz[x]>sz[mx]) { mx=x; } } } heavychild[node]=mx; if (leaves[node]%2==1) leaves[node]=1; else leaves[node]=2; } void heavy_order(int node, int parent, int capat) { timer++; stamp[node]=timer; revstamp[timer]=node; pathend[node]=capat; if (heavychild[node]==0) return; heavy_order(heavychild[node],node,capat); for (auto x : nodes[node]) { if (x!=parent && x!=heavychild[node]) { heavy_order(x,node,x); } } } signed main() { /* ifstream fin("arbore.in"); ofstream fout("arbore.out"); */ ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int q,i,j,uu,v,d,total_leaves; cin >> n >> q; for (i=1; i<=n-1; i++) { cin >> uu >> v; nodes[uu].push_back(v); nodes[v].push_back(uu); } for (i=1; i<=n; i++) { if (nodes[i].size()!=1) { root=i; break; } } h[root]=0; ans=0; dfs(root,-1); total_leaves=leaves[root]; timer=0; heavy_order(root,-1,root); hevi.build(1,n,1); for (i=1; i<=q; i++) { ans=0; cin >> d; for (j=1; j<=d; j++) { cin >> u[j]; ans++; if (nodes[u[j]].size()!=1) { total_leaves++; hevi.add_leaf(u[j]); } nodes[u[j]].push_back(n+j); if (is_leaf[u[j]]) { if (nodes[u[j]].size()%2==0 && nodes[u[j]].size()>=4) ans--; else if (nodes[u[j]].size()%2==1) ans++; } } if (total_leaves%2==0) { ans+=n-1; ans+=hevi.query(1,n,1,1,n); ans-=hevi.query(1,n,1,stamp[root],stamp[root]); cout << ans << "\n"; } else cout << "-1\n"; for (j=1; j<=d; j++) { nodes[u[j]].pop_back(); if (nodes[u[j]].size()!=1) { hevi.remove_leaf(u[j]); total_leaves--; } } } return 0; }